ok i diddnt find this in a couple of quick searches that i tried so if it is a report i am sorry.
Basically what you do is, (im speaking from ally pov), go to elwenn forest and find someone fighting a mob...put curse of recklessness on the mob and watch the ally get pwnt because of the buff on the curse and the fact that it is immune to fear.....
If you go to a horde starting point, such as bree you can put curse of weakness on the person if they are flagged, or recklessness on the mob if not...and it will do the same thing, either make them hit the mob so softly they die or the mob will become so powerfull it will 3 shot them.
ok go have fun6):
/flame shield
[edit] - the reson this IS an exploit is because blizzard doesnt want you to kill your own faction for one thing, and for another level 70s arnt supposed to to to level 1 - 20 areas to nuke everything in thier sight